Before human embryonic stem (hES) cell-based therapies (e.g., for such conditions as neuronal disease, cardiovascular disease, diabetes, Parkinson's, among others) can be translated into the clinic, we must develop new strategies that can overcome the immunological barrier. To address this critical bottleneck, we have assembled an interdisciplinary team of investigators who are focused on developing novel and effective strategies to induce immunological tolerance for hES cell therapy. Our ability to overcome the immunological response will be a major scientific advance in stem cell biology.